Known cyclone separators, see documents DE 10 2004 033 677 A1, DE 203 00 596 U1, DE 10 2004 002 310 A1, DE 10 2004 019 154 A1, EP 1 614 871 A2, DE 10 2004 006 082 A1, JP 2005 155 423 A, comprise an essentially cylindrical vortex chamber with a tangential gas inlet. The helical gas vortex runs out in a cone wall and by means of an immersion tube provided in the region of the gas inlet, is extracted in the opposite direction through the interior of the gas vortex, such that a flow reversal of the gas occurs. Separated particles exit through an aperture for example in the tip of the cone wall. The manufacture of cyclone separators with closed chamber requires very elaborate injection moulds and is extremely difficult, which is why it was suggested with DE 10 2004 019 154 A1 to construct such cyclones from two parts to be manufactured with simple moulds.
Document DE 10 2004 016 742 B3 discloses an oil separator with a reed valve on the inlet side and a diffuser arranged downstream. Because of inertia owing to the sharp deflection of the gas, oil particles are separated on the wall surrounding the tip of the reed.